Nepalese policemen walk with a sniffer dog at the site of a bomb blast on February 27, 2012.

Story highlights

Bombing occurs near central secretariat in Nepal's capital

Previously unknown group claims responsibility, police say

Two people were killed on the spot, and another died at a hospital

Kathmandu, Nepal CNN  — 

Three people were killed and seven others injured, two of the seriously, when an improvised explosive device went off Monday near government offices here.

It is unclear who is behind the blast, a rare occurrence in the Himalayan capital, although a previously unknown group, United Ethnic Liberation Front, has claimed responsibility, police Officer Dhiraj Singh said.

“We cannot verify that as we are still investigating,” Singh said. No arrests have been made so far.

The explosion happened outside a court house and less than 200 meters from the Central Secretariat, which houses most government ministries.

Two people died on the spot while third died while undergoing treatment at hospital. All 10 victims are men.

As Nepal prepares a new republican constitution and adopts a federal model, various ethnic groups in a population of about 27 million are demanding special rights and calling for provinces based on ethnicity.